Date: Thu, 9 Apr 2009 14:56:51 -0400
Reply-To: Mark Mellum <mark**At_Symbol_Here**GFSCHEMICALS.COM>
Sender: DCHAS-L Discussion List <DCHAS-L**At_Symbol_Here**LIST.UVM.EDU>
From: Mark Mellum <mark**At_Symbol_Here**GFSCHEMICALS.COM>
Subject: Re: Mixtures of Oleum and Perchloric acid
Comments: To: Little Helga
In-Reply-To: <B478FE90ACFE421EBA0487FEAA0FCD92**At_Symbol_Here**yourfsyly0jtwn>

Anhydrous perchloric acid is not stable and sulfuric acid will not help to stabilize it.  I would expect such a mixture to explode within minutes if not immediately.  This procedure is not the same as making perchloric acid in acetic acid for use as a non-aqueous titrant.  In that solution, the perchlorate is still in the form of a dihydrate so is stable.  Sulfuric acid and oleum are strong dehydrating agents that will remove the water of hydration from perchloric acid, making it unstable.

GFS Chemicals has a long history of making perchloric acid and perchlorate salts.  In the past, we made anhydrous perchlorate as a raw material that was consumed shortly after being made.  We stopped that practice more than 30 years ago.  I forwarded this email to our retired chief chemist for his comments.  He actually worked with anhydrous perchloric acid during his tenure here.  While I wait for his response I felt compelled to send this warning. 

Best regards,
Mark Mellum
Regulatory Compliance Manager
GFS Chemicals, Inc. 
614-224-5345 x 112
Fax  614-225-1175

Please visit our catalog at our website:



Limitation on GFS Product Use, Warranties and Liability: see below or for complete Terms and Conditions go to Terms and Conditions


Unless otherwise specifically certified in writing by an Officer of GFS Chemicals, Inc. (GFS), GFS products are not intended, approved or authorized for human or animal consumption nor for direct use in any food, drug or cosmetic applications. GFS products are warranted to meet our specifications as set forth in the GFS Lot Analysis or other Company literature specifically relating thereto only. By accepting GFS' products, Customer agrees to the limitations set forth herein, assumes all responsibility for the proper use of such products in accordance with these limitations, and agrees to indemnify, defend and hold harmless GFS from and against any and all claims, suits and/or liability in the event such products are used in a manner contrary to these limitations. GFS HEREBY DISCLAIMS ANY AND ALL WARRANTIES, LIABILITY AND/OR RESPONSIBILITY IN CONNECTION WITH ANY USE OR APPLICATION OF ITS PRODUCTS IN A MANNER CONTRARY TO THE LIMITATIONS SET FORTH HEREIN AND/OR SOLD AS REPACKED COMPANY BRANDED MATERIALS TO THIRD PARTIES.  ANY USE OR APPLICATION OF GFS PRODUCTS IN A MANNER CONTRARY TO THESE LIMITATIONS SHALL BE AT THE USER'S SOLE RISK, AND SHALL RELIEVE GFS OF ALL WARRANTIES, LIABILITY AND RESPONSIBILITY WITH RESPECT THERETO. These limitations may not be modified, affected or superseded by Customer, nor by any language, term or provision contained in Customer's purchase order, confirmation or other correspondence or communication. ONLY AN OFFICER OF GFS CHEMICALS MAY ALTER GFS STANDARD TERMS AND CONDITIONS. RELIANCE ON CONTRADICTORY STATEMENTS, WHETHER VERBAL OR WRITTEN, BY NON-AUTHORIZED GFS EMPLOYEES THAT WOULD ALTER THESE STANDARD GFS TERMS AND CONDITIONS IS STRICTLY PROHIBITED.

This communication is for use by the intended recipient and contains information that may be privileged, confidential or copyrighted under applicable law. If you are not the intended recipient, you are hereby formally notified that any use, copying or distribution of this e-mail, in whole or in part, is strictly prohibited. If you are not the intended recipient please notify the sender by return e-mail and delete this e-mail from your system. This e-mail does not constitute a contract offer, a contract amendment, or an acceptance of a contract offer. This e-mail does not constitute a consent to the use of sender's contact information for direct marketing purposes or for transfers of data to third parties.

From: DCHAS-L Discussion List [mailto:DCHAS-L**At_Symbol_Here**] On Behalf Of Little Helga
Sent: Wednesday, April 08, 2009 6:52 PM
To: DCHAS-L**At_Symbol_Here**LIST.UVM.EDU
Subject: [DCHAS-L] Mixtures of Oleum and Perchloric acid

Does anyone know of a potential hazard of mixing 70% perchloric acid with oleum (% SO3 to react with most of the water in the perchloric acid).


The research group is trying to make ~100% sulfuric acid and ~100% perchloric acid to oxidize small quanities of carbon (graphite) at temperatures ranging up to 70 C. The group understands the usual problems with handling oleum and they know that 100% perchloric acid by its self is a major safety problem.


Concentrations of the "100% perchloric acid" would be in the range of 10 to 30% in the oleum.


Bob Small

RS Associates

Tucson, AZ


Previous post   |  Top of Page   |   Next post

The content of this page reflects the personal opinion(s) of the author(s) only, not the American Chemical Society, ILPI, Safety Emporium, or any other party. Use of any information on this page is at the reader's own risk. Unauthorized reproduction of these materials is prohibited. Send questions/comments about the archive to
The maintenance and hosting of the DCHAS-L archive is provided through the generous support of Safety Emporium.